/*
 * Copyright 2015 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.social.connect.web;

import org.springframework.social.connect.Connection;
import org.springframework.social.connect.ConnectionFactoryLocator;
import org.springframework.social.connect.UsersConnectionRepository;
import org.springframework.web.context.request.RequestAttributes;

/**
 * Helper methods that support provider user sign-in scenarios.
 * @author Keith Donald
 */
public class ProviderSignInUtils {

	private SessionStrategy sessionStrategy;
	private ConnectionFactoryLocator connectionFactoryLocator;
	private UsersConnectionRepository connectionRepository;


	public ProviderSignInUtils( ConnectionFactoryLocator connectionFactoryLocator,UsersConnectionRepository connectionRepository) {
		this(new HttpSessionSessionStrategy(),connectionFactoryLocator,connectionRepository);
	}
	
	public ProviderSignInUtils(SessionStrategy sessionStrategy,ConnectionFactoryLocator connectionFactoryLocator,UsersConnectionRepository connectionRepository) {
		this.sessionStrategy = sessionStrategy;
		this.connectionFactoryLocator = connectionFactoryLocator;
		this.connectionRepository = connectionRepository;
	}

	/**
	 * Get the connection to the provider user the client attempted to sign-in as.
	 * Using this connection you may fetch a {@link Connection#fetchUserProfile() provider user profile} and use that to pre-populate a local user registration/signup form.
	 * You can also lookup the id of the provider and use that to display a provider-specific user-sign-in-attempt flash message e.g. "Your Facebook Account is not connected to a Local account. Please sign up."
	 * Must be called before handlePostSignUp() or else the sign-in attempt will have been cleared from the session.
	 * Returns null if no provider sign-in has been attempted for the current user session.
	 * @param request the current request attributes, used to extract sign-in attempt information from the current user session
	 * @return the connection
	 */
	public Connection<?> getConnectionFromSession(RequestAttributes request) {
		ProviderSignInAttempt signInAttempt = getProviderUserSignInAttempt(request);
		return signInAttempt != null ? signInAttempt.getConnection(connectionFactoryLocator) : null;
	}
	
	/**
	 * Add the connection to the provider user the client attempted to sign-in with to the new local user's set of connections.
	 * Should be called after signing-up a new user in the context of a provider sign-in attempt.
	 * In this context, the user did not yet have a local account but attempted to sign-in using one of his or her existing provider accounts.
	 * Ensures provider sign-in attempt session context is cleaned up.
	 * Does nothing if no provider sign-in was attempted for the current user session (is safe to call in that case).
	 * @param userId the local application's user ID
	 * @param request the current request attributes, used to extract sign-in attempt information from the current user session
	 */
	public void doPostSignUp(String userId, RequestAttributes request) {
		ProviderSignInAttempt signInAttempt = (ProviderSignInAttempt) sessionStrategy.getAttribute(request, ProviderSignInAttempt.SESSION_ATTRIBUTE);
		if (signInAttempt != null) {
			signInAttempt.addConnection(userId,connectionFactoryLocator,connectionRepository);
			sessionStrategy.removeAttribute(request,ProviderSignInAttempt.SESSION_ATTRIBUTE);
		}		
	}

	// internal helpers
	
	private ProviderSignInAttempt getProviderUserSignInAttempt(RequestAttributes request) {
		return (ProviderSignInAttempt)sessionStrategy.getAttribute(request, ProviderSignInAttempt.SESSION_ATTRIBUTE);
	}
	
}